The first high-resolution visible image from Mars Odyssey shows the well known dark streaks in Acheron Fossae:

The first THEMIS visible camera image - Acheron Fossae
http://themis.asu.edu/latest/zoom-first_vis.html

According to the March 1st news conference MO will be able to map the entire planet in visible light color imaging at 20 meter resolution. Dark streaks are already known to be forming currently, so MO should be able to see before and after images of dark streaks at a yearly time scale.

Some researchers such as Nick Hoffman have suggested the Malin/Edgett gullies are also forming currently:

From: Robert Clark (rgregoryclark@yahoo.com)
Subject: Mars gullies forming currently?
Newsgroups: sci.astro, alt.sci.planetary, sci.physics, sci.geo.geology
Date: 2002-01-22 00:53:07 PST
http://groups.google.com/groups?th=77870473d53ce66e

Are the Malin/Edgett gullies wider than the 20 meter scale to be visible by the Mars Odyssey imager?

Bob Clark